The conventional automatic umbrella as well as non-automatic umbrella employs more than a coil spring to facilitate the unfolding and collapsing of the umbrella. And the way thereof to dispose the coil springs is by means of connecting, in the case of which the number of connecting point is consequently increased. As a result, the connecting points in numbers will decrease the durability of the umbrella, but also heighten the cost thereof.
Besides, the conventional arts concerned employ more than a set of spokes to prop up the unfolded umbrella. The trouble is, that the cost is heightened and the time for manufacturing thereof is wastefully lengthened.
Apart from the drawbacks abovementioned, the conventional arts concerned have also others. For example, they have as yet no provision of a device to prevent the turning inside out thereof and no provision of a device to adjust the tensity of the umbrella cloth.